docs: def alpha_cased(text, lower=False):
      """
      Filter text to just letters and homogenize case.
      
      :param str text: what to filter and homogenize.
      :param bool lower: whether to convert to lowercase; default uppercase.
      :return str: input filtered to just letters, with homogenized case.
      """
      text = "".join(filter(
              lambda c: c.isalpha() or c == GENERIC_PROTOCOL_KEY, text))
      return text.lower() if lower else text.upper()